Metabolic Changes of Aflatoxin B1 to become an Active Carcinogen and the Control of this Toxin
Immunome Research

Immunome Research
Open Access

ISSN: 1745-7580

Review Article - (2015) Volume 11, Issue 2

Metabolic Changes of Aflatoxin B1 to become an Active Carcinogen and the Control of this Toxin

Magda Carvajal-Moreno*
Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México. Ciudad Universitaria, Coyoacán, 04510 México DF, Mexico
*Corresponding Author: Magda Carvajal-Moreno, Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán, 04510 México DF, México, Tel: +52 55 5622 1332 Email:


Although aflatoxins are unavoidable toxins of food, many methods are available to control them, ranging from natural detoxifying methods to more sophisticated ones. The present review englobes the main characteristics of Aflatoxins as mutagens and carcinogens for humans, their physicochemical properties, the producing fungi, susceptible crops, effects and metabolism. In the metabolism of Aflatoxins the role of cytochromes and isoenzymes, epigenetics, glutathione-S-transferase enzymes, oncogenes and the role of aflatoxins as mutagens of the tumor suppressor gene p53, and the Wnt signaling pathway are briefly explained, as well as these toxins as biomarkers.

The last section includes the Aflatoxin control methods, from the protection of the crop from the Aspergillus fungi, the biocontrol solution, the AFB1-DNA adduct control with the natural repair rates of adduct removal, induction to resistance to AFB1, the detoxification enzymes, recombinant yeasts, pre-exposure to Aflatoxin M1, the inhibition of AFB1 lesions by different compounds, chemoprevention and protective chemical compounds, cruciferous vegetables, dietary dithiolethiones, glucoraphanin, indol-3-carbinol, oltipraz, phenols (butylated hydroxytoluene and ellagic acid), indomethacin, selenium, natural nutrients, coumarin chemoprevention, cafestol and kahweol, terpenes and monoterpenes, grapefruit juice, vitamins, traditional Chinese medical plants (Oldenlandia diffusa and Scutellaria barbata), chlorophyllin, probiotic bacteria and additives as aluminosilicates and glucomannans are described here. Finally, the aflatoxin international legislation was briefly described.

Keywords: Aflatoxins; Mutagens; Carcinogens; Control


The FAO [1] of the United Nations estimates that 25% of the world’s food crops and their derivatives are contaminated with mycotoxins, which threaten human health [2]. Moreover, the Center for Disease Control from USA [3] estimates that more than 4.5 billion people in the developing world are exposed to aflatoxins (AFs).

The contamination of food supplies by naturally occurring toxins is of particular concern in the rural communities of developing countries [4]. AFs are the most frequent and toxic mycotoxins, and their metabolism and mechanisms to control them are of upmost importance.

The FAO [1] of the United Nations estimates that 25% of the world’s food crops and their derivatives are contaminated with mycotoxins, which threaten human health [2]. Moreover, the Center for Disease Control from USA [3] estimates that more than 4.5 billion people in the developing world are exposed to aflatoxins (AFs).

The contamination of food supplies by naturally occurring toxins is of particular concern in the rural communities of developing countries [4]. AFs are the most frequent and toxic mycotoxins, and their metabolism and mechanisms to control them are of upmost importance.


AFs are secondary metabolites, i.e., polyketides that chemically correspond to a bisdihydrodifuran or tetrahydrobisfuran united to a coumarin substituted by a cyclopentanone or a lactone [5-7]. AFs are divided into two subgroups [6,8,9]:

a) Bisfuran-coumarin-cyclo pentanons, which include AFs of series B (AFB1, AFB2, AFB2a), M (AFM1, AFM2, AFM2a), Q (AFQ1), P (AFP1), and aflatoxicol (AFL) that interconverts with AFB1.

b) Bisfuran-coumarin-lactones, which contain AFs of series G (AFG1, AFG2, AFG2a).

Only AFB1, AFB2, AFG1 and AFG2 are naturally synthesized by toxigenic fungi. The other AFs (M1, M2, P1, Q1, G2a, B2a and AFL) are products of microbial or animal metabolism [9-13].

The liver of animals protects the organism by lowering the toxicity of AFB1 via the addition of a OH- group to form hydroxylates (AFM1, AFP1, AFQ1, and AFL); this step make AFs soluble in water and facilitates their disposal via urine, feces and milk. AFB1 and AFG1 have a double bond at the 8,9 position that oxidizes and forms AFB1-exo-8,9-epoxide (AFBO), an unstable molecule, which produces dihydrodiol AFB1 and is linked to the N7-guanine of DNA [14] to form active carcinogens called AFB1-DNA adducts. AFB2 and AFG2 [15] lack a double bond, which affects their toxicity. The bond changes that convert AFB1 to AFB2 are known [14,16], and the biotransformation and biosynthetic routes of AFB1 have been described [17-20].

Physicochemical properties

AFs are white to yellow odorless and flavorless crystalline solids that are soluble in organic solvents and insoluble in water. They fluoresce when excited under ultraviolet light, are thermo-resistant, and have a low molecular weight (MW). Furthermore, their physicochemical properties are distinct [21,22]. AFs have high points of fusion and decomposition temperatures in the range of 237°C (AFG2) to 320°C (AFP1) [23,24]. Therefore, AFs are stable at temperatures present when cooking or boiling food, milk ultrapasteurization and alcoholic fermentation.

Acid or alkaline solutions heated to temperatures higher than 100°C lead to decarboxylation with the opening of the lactone ring, which results in the loss of the methoxy radical of the aromatic ring and a loss of fluorescence. The formation of the acid ring [25] during human digestion [26] reverses this hydrolysis.

Lime treatment of maize disguises but does not eliminate AFs. Oxidative and reductive agents react with AFs to change their molecular structure and hydrogenate AFB1 and AFG1 to produce AFB2 and AFG2 [22]. In the presence of inorganic acids, AFB1 and AFG1 are transformed into B2a and G2a [22,27]. AFB2a is 1000 times less mutagenic than AFB1 [23].

Producing fungi

Aflatoxins are the most toxic and frequent mycotoxins. They are produced by the mold Aspergillus spp., which belongs to the Kingdom Fungi, Phylum Ascomycota, Order Eurotiales, Class Eurotiomycetes, Family Trichocomaceae, and Genus Aspergillus. The main aflatoxigenic species are A. flavus [28-31], A. parasiticus [32-39] and A. nomius [40,41]. A. tamarii was reported to produce AFs and cyclopiazonic acid [42].

Other reports state that A. tamarii, A. oryzae, A. versicolor, Penicillium commune, and P. griseofulvum, as AF producers, are proven misidentifications [43]. Aspergillus chevalieri,A. repens, A. versicolor,Cladosporium herbarum, Penicillium chrysogenum and Phoma glomerata remain identified as AF producers [44].

Susceptible crops

Aflatoxins contaminate cereals (maize, sorghum, rice, barley, and oats), oilseeds (peanuts, cottonseed, nuts, pistachios, almonds, hazelnuts, cacao, and coconut), dry fruits (figs, dates, and raisins), spices (black pepper, hot pepper, and cumin), and the seeds and grains of crops before and after harvest. In the field, AFs are produced in drought-stressed conditions.

AFs pass to meats, dairy products, eggs, etc., via microbial or animal metabolism. Mexico was considered the country with more liver diseases in the American continent [45], and AFs have been reported in several natural and processed foods, such as maize tortillas [46], rice [47], chilies [48], milk [49,50], eggs [51], chicken breast [52], etc.


AFs are dangerous toxins, and their toxicity can be ranked as follows: AFB1>AFG1>AFG2>AFB2 [53]. AFB1 is considered the most dangerous AF of the group and is a potent teratogen, mutagen and carcinogen [54,55]. Exposure to AFs occurs primarily via the ingestion of contaminated foods [56], but it is also absorbed through the skin, and spores in the air are inhaled, causing hepatic and gastrointestinal injuries. AFs are among the most potent carcinogens to humans, i.e., Group I carcinogens [55], and they are acutely hepatotoxic and immunosuppressive in a variety of animals [17,57-59]. AFs can cause acute or chronic effects depending on the duration and level of exposure [60]. The ingestion of higher doses of AF can result in acute aflatoxicosis, a condition characterized by hemorrhage, vomiting, diarrhea, abdominal pain, lung edema, digestive changes, hepatotoxicity, fatty and necrotic liver [61], liver failure and death [56]. Severe acute liver injury with high morbidity and mortality has been associated with high-dose exposure to AF [62], and the ingestion of 2 to 6 mg/day of AFs for one month can cause acute hepatitis and death [63,64].

Chronic low-level AF exposure can increase the risk for cancers, mainly hepatocellular carcinoma (HCC) [65], in areas where hepatitis B virus (HBV) infection is endemic because there a synergism between the HBV and AFB1 that increases the risk. Children younger than five years remain the most vulnerable population, with exposure damaging their immunity and causing dwarfism [66]. Other symptoms are immunosuppression [67,68], and AFs also reduce the protection given by vaccinations [69]. Furthermore, they cause miscarriages, fetal malformations [70], hepatitis B and C, cirrhosis [64,71], Reye syndrome with encephalitis and fatty liver [72], marasmus, Kwashiorkor [73], and death [74].

The worst human outbreaks of aflatoxicosis were reported in India [4,64,71], Kenya [3,74-78], Nigeria [79], Gambia [80], Uganda [81-83], Swaziland [84-85], Mozambique and Transkei [86,87], Thailand [30,88], Malaysia [89], China [59,90-93], Taiwan [94], New Zealand [95] and the Philippines [96].

Regarding the prevalence and human exposure to AFs, approximately 4,500 million persons living in developing countries are recognized to be chronically exposed to largely uncontrolled amounts of AFs [97,98].


Role of cytochromes and isoenzymes

Cytochrome P450 enzymes (CYPs 450) are hemoproteins and electron carriers that catalyze or accelerate oxidation-reduction reactions during cellular respiration [99], and they are the main enzymes involved in the metabolic activation of AFs [100]. In the past, CYPs 450 were considered to specifically originate from the liver, but they are now known to be distributed throughout the body [101]. Nevertheless, the liver is the main organ that metabolizes xenobiotics [102].

AFB1 is metabolized in the body by CYP450 isoforms such as CYP1A1 and CYP1A2, which comprise 10% of CYP450 isoforms, CYP3A4 (30%), CYP2Cs (20%), CYP3A5, and CYP3A7 [102] in the fetus. AFB1 is also metabolized by glutathione S-transferase (GST) and AFB1-aldehyde reductase, leading to reactive metabolites, some of which can be used as AF exposure biomarkers [103].

CYP1A1 and CYP1A2 transform and activate procarcinogens as intermediate metabolites that link to DNA and participate in the activation of AFB1 [104-107]. In humans, the CYP1A2 isoenzyme is encoded by the CYP1A2 gene [108].

The CYP1A2 enzyme isoform is the principal metabolizer of AF at low concentrations, whereas CYP3A4 isoform acts as metabolizer for high AF amounts. The accumulation of AFB and its metabolites in the body, especially AFBO, depletes glutathione (GSH) due to the formation of high amounts of epoxides and other reactive oxygen species.

Inflammatory liver disease increases the expression of specific CYP450 isoenzymes involved in AFB1 activation. The immunohistochemical expression and localization of various human CYP450 isoforms, including CYP2A6, CYP1A2, CYP3A4, and CYP2B1, have been examined. Alterations in the phenotypic expression of specific P450 isoenzymes in hepatocytes associated with hepatic inflammation and cirrhosis might increase the susceptibility to AFB genotoxicity [103].

A human cell line stably expressing human CYP3A4 has been used to study its role in the metabolic activation of AFB1 and compare this role to those of CYP1A2 and CYP2A3 [109]. The human lymphoblastoid cell line 1A2/Hyg was 3- to 6-fold more sensitive to AFB1-induced mutation than the 3A4/Hol cell line. Furthermore, 3A4/HoI cells, which stably express human CYP3A4 cDNA, were 10- to 15-fold more sensitive to the AFB1 mutation than 2A3/Hyg cells [109].


Epigenetic changes are heritable changes in gene expression that do not involve changes to the underlying DNA sequence, i.e., a change in phenotype without a change in genotype. Epigenetic changes refer to external modifications of DNA that turn genes "on" or "off." These modifications affect how cells "read" genes, resulting in changes in gene expression, cellular differentiation and growth without changing the genetic code itself. AFB, AFBO and other metabolites also affect epigenetic mechanisms, including DNA methylation, histone modifications, the maturation of microRNAs (miRNAs) and the daily formation of single nucleotide polymorphisms (SNPs). Specifically, AFB exposure may facilitate the process of change and induce G:C to T:A transversions at the third base in codon 249 of TP53, causing p53 mutations in HCC [110]. AFB also promotes tumorigenesis, angiogenesis, invasion and metastasis in HCC via epigenetic mechanisms. Chronic AF exposure leads to the formation of reactive AFBO metabolites in the body that could activate and de-activates various epigenetic mechanisms, leading to development of various cancers [103].

The effects of AFB1 intake, genetic polymorphisms of AFB1 metabolic enzymes, and interactions between nucleotides were studied with regard to the risk of gastric cancer in Korean populations. The probable daily intake of AFB1 was significantly higher (p<0.0001) among gastric cancer patients than among control subjects. Only CYP1A2 was associated with the genetic polymorphisms present in gastric cancer. The effect of AFB1 on gastric carcinogenesis may not be modulated by genetic polymorphisms of AFB1 metabolic enzymes [111].

Glutathione S-transferase enzymes (GSTs)

In Phase I of metabolic processes water-soluble products are generated. In Phase II, GSTs allow these metabolites to combine with polar endogenous molecules to form conjugation products that are rapidly excreted [112,113]. This reaction increases the solubility of dangerous compounds, allowing them to be excreted [114].

GSTs are a family of enzymes that protect the organism and are present in Phase II of enzymatic detoxification of many electrophilic metabolites [115,116], such as xenobiotic derivatives and endogenous molecules (antibiotics, steroids, prostaglandins and leukotrienes) [112], which exert carcinogenic and genotoxic effects [117].

GSTs were first purified from rat liver. Enzyme inhibition can also be used to control AFs microsomes [115] in the soluble fraction in the cytoplasm (cytosolic fraction), but GSTs are also found in the nucleus, mitochondria and peroxisomes [117]. GSTs from mammals are the best-characterized enzymes that facilitate the detoxification route of dangerous components that conjugate with glutathione (GSH) [113]. GSH is an important antioxidant that prevents damage to important cellular components by reactive oxygen species, such as free radicals, peroxides, lipid peroxides and heavy metals [118].

Each subunit of GST features a specific linkage site (place-G) and an electrophilic linkage site (place-H), which is less specific and reacts with different toxic agents [118]. GSTs link to lipophilic molecules with a molecular mass >400 Daltons (hemin, bilirubin, biliary salts, steroids, thyroid hormones, fatty acids and drugs) and store and transport them to the aqueous phase of the cell [114,119].

Glutathione S-transferase and aflatoxins

AFB1 includes the reactions of enzymatic conjugation mediated by GST to inactivate the AFBO. Spontaneously, AFBO is hydrolyzed to 8,9 dihydrodiol and conjugates with GSH to form AFB1-gluthation transferase (AFB1-SG) [120]. The conjugate AFB-SG is the most abundant biliary metabolite and is excreted by urine [89]. The induction of GST and aldehyde-AFB1 reductase prevents the formation of AF-ADN and AF-protein adducts and blocks carcinogenesis in rats [121]. Specifically, the induction of GST prevent the union of AFB1 and ADN in different species [122]. The dietary ingestion of antioxidants increases the levels of GST, which consequently increases the elimination of AFB-SG in the urine of treated animals [90].

Oncogenes and the tumor suppressor gene p53

Oncogenes, such as N-ras, c-myc or c-fos, are over-expressed, but their mutations are rare, and evidence to directly implicate these mutations in HCC is rare [123]. A specific mutation in codon 249 of the p53 gene is present in regions where HCC and exposure to AFs are prevalent [124]. The mutation induced by the reactive forms of AFB1 in codon 249 of the p53 gene is a “hotspot” for the mutation induced by AFB1, specifically the transversion GC→TA [125]. In Gambia, this mutation was detected in the DNA of HCC patients but was rare in control patients [126-128]. The transversion G→T or transition G→A is produced in the third base of codon 249 of the p53 gene and in the first or second base of codon 12 of the H-ras gene [129-134]. When rats, mice and fish ingest an AF-contaminated diet, some proto-oncogenes of the “ras” family are activated [135,136]. High incidences of activated Ki-ras and N-ras have been observed in liver carcinomas and adenomas induced by AFB1 [135].

Expression and activation of several c-oncogenes in seven hepatocellular carcinomas from seven separate rats treated with AFB1 were examined by Northern and Southern blot analyses. Both c-Ha-ras and c-myc transcripts were elevated at high levels in all hepatomas. Moreover, in one of them, T2-1 hepatoma, the c-myc gene was amplified only in a tumor part of liver without significant rearrangement. N-ras specific transcripts were not elevated in these hepatomas. The consistently increased expression or deregulation of the c-myc and c-Ha-ras genes may play an important role in the development of hepatomas induced by AFB1 [137]. When male Fisher rats were exposed to AFB1 and AFG1, four liver tumors were induced: three harbored activated N-ras and one exhibited the transversion G→A in codon 12 of Ki-ras [138,139].

The identification of a specific mutation in the tumor suppressor gene p53 in HCC in regions where AF exposure is high has helped to identify an AF biomarker [140]. A nonsense mutation in p53 that yields a broken, non-functional protein provides a selective advantage for the expansion of preneoplastic or neoplastic cells. The p53 gene plays a molecular role in cancer and consequently serves as an intermediate biomarker for cancer development [141].

The suppressor p53 gene is mutated in 53% of HCC cases in Mexico, a country in which exposure to AFB1 is high, while whereas in populations with low exposure to this toxin, mutations were identified in 26% of HCC cases [142]. In Senegal, where people are exposed to high concentrations of AFB1 via foodstuffs, the 249 codon mutation of the p53 gene was found in 10/15 HCC tumors [143]. The mutation index of the p53 gene is higher in tumors associated with HBV compared with tumors associated with the hepatitis C virus (HCV) and non-viral HCC, independent of AF exposure [144].

Wnt signaling pathways

The Wnt (=Wingless-related integration site in Drosophila melanogaster) signaling pathways are a group of signal transduction pathways that rely on proteins that pass signals from the outside of a cell to the inside of the cell via cell surface receptors [145,146].

Wnt signaling was first identified due to its role in carcinogenesis and embryonic development (cell fate specification, proliferation, migration, and body axis patterning). Its role in embryonic development was discovered when genetic mutations in proteins in the Wnt pathway produced abnormal fruit fly embryos. The genes responsible for these abnormalities also influence breast cancer development, prostate cancer, glioblastoma, type II diabetes and other diseases [145,146].

The inappropriate reactivation of the Wnt pathway as a result of mutations in the β-catenin gene which encodes a protein that facilitates the mobility of neoplastic cells) is implicated in the development of HCC [147]. Mutations in the β-catenin gene can activate the transcription of Wnt target genes, such as c-myc, cyclin D1 and PPARδ. Therefore, these mutations can promote tumor progression by stimulating cellular proliferation [147,148].

AFB1 negatively regulates the Wnt/β-catenin signaling pathway by activating microRNA-33a (miR-33a). MicroRNAs modulate gene expression in various cancers and cardiovascular disorders, but only a few of microRNAs are associated with the pathology of AFB1. A regulatory network involving AFB1, miR-33a and β-catenin in human carcinoma cells showed that the level of miR-33a increases the response of HCC cells to AFB1, whereas β-catenin expression decreased in the same cells when they were treated at their IC50 values. miR-33a decreases the expression of β-catenin, which affects the β-catenin pathway and inhibits cell growth. AFB1 might decrease the response of β-catenin by increasing the response of miR-33a, promoting the proliferation of malignant cells [149].


An exposure biomarker refers to the measurement of AFs, their metabolites or interactive specific products in a compartment of the body or fluids to assess past and present exposure. The biomarkers of internal doses and from biologically effective doses of AF are generally hydroxylated metabolites, and AF-DNA adducts formed from epoxide derivatives [150].

The biomarkers identified in etiological research have been used for preventive purposes in high-risk populations because experimental studies have established time links between AF biomarker modulation and the risk of disease. The early identification of AF metabolites in human fluids [151] stimulated the development of biomarkers [152]. The availability of specific antibodies helps the detection of AF metabolites in human urine [153-155].

AFB1 is biotransformed to various metabolites, especially active AFBO, which interacts with DNA, RNA and various metabolic pathways, such as protein synthesis, the glycolytic pathway and the electron transport chain, which is involved in ATP production in cells. AFB interacts with DNA to form AFB-DNA adducts to cause DNA mutations and breakages.

CYP450 controls AF adduct formation in the metabolic route AFB1. AFBO is the electrophilic metabolite that links to N7 of the guanine residues of DNA to form 8,9-dihydroxy-8-(N7) guanyl-9-hydroxy AFB1 adducts (AFB1-Gua), that which is the most abundant [125,156,157]. The imidazol ring on the positively charged AFB1-Gua promotes the depurination and produces an apurinic site. This ring opens to form a chemically and biologically more stable adduct, formamidopyrimidine,2,3-dihydro-2-(N-formyl)-2´,5´,6´-triamino-4´-4´-oxy-N-pyrimidyl-3-hydroxy-AFB1 (AFB1-FAPY) adduct present in the DNA replication several times [158,159].

One hour after injecting rats with AFB1, AFB1-Gua comprised the majority of adducts, whereas the adduct AFB1-FAPY was predominant at later time points [160]. The apurinic sites, AFB1-Gua and AFB1-FAPY, individually or collectively act as the precursors of the genetic effects of AFB1, and these two adducts develop the tumors.

Tumors were induced in rats to study the human Ha-ras proto-oncogene, which is metabolically mutated by AFB1, using an in vitro transfection of a plasmid modified with AFB1. In this experiment, G→T transversions were identified in the first and second bases of codon 12. The proto-oncogene Ha-ras mutated by AFB1 was identified in its in vitro oncogenic form, but this mutation has not yet been reported in human HCC patients exposed to AFB1 [161].

Therefore, identifying the presence of free AFs (AFB1, AFB2, AFG1, AFG2) is important to assess a person’s exposure to AFs via food, Furthermore, measuring the metabolic hydroxylates (AFM1, AFM2, AFP1 and AFL) is important as a biomarker of the internal dose. Finally, the effective biological doses in control liver and human HCC samples as well as the presence of AFB1- Gua and AFB1-FAPY adducts serve as etiologic agents of cancer.


Protecting harvests from Aspergillus fungus

AF contamination can occur before harvest when the crop undergoes drought stress at the grain filling stages and when wet conditions occur during harvest periods. AF contamination increases with insect damage, delayed harvesting and high moisture levels during storage and transportation. Therefore, additional irrigation in the fields and the control of insects reduces AF contamination. In storage, AFs can be controlled by maintaining available moisture at levels below those in the range of the growth of Aspergillus spp. Cultural practices, such as resistant crops and competitive exclusion using strains that do not produce AF, can block AF production.

AF destruction depends on the food water content, pH, application of propionic acid against the fungus, presence of ionic compounds, and electric charge. The degradation mechanism is not completely understood, but the lactone ring opens, allowing a decarboxylation at temperatures above 150°C that were necessary to attain partial destruction of the toxin [22]. The effects of pH (5.0, 8.0, 10.2), temperature (121°C 130°C 140°C) and heating time (5 s, 20 s, 15 min) on mutagenic activity (assayed by Ames test) of peanut beverages artificially contaminated with AFB1. Heat treatments at pH 8.0 were not effective in reducing the mutagenic activity. On the other hand, the treatments pH 10.2, 130°C 20 s and pH 10.2, 121°C 15 min reduced the mutagenic activity by 78% and 88%, respectively [22].

Biocontrol solution

The goal of the “Aflatoxin Control in Maize and Peanuts Project” is to develop and implement holistic strategies to address AF contamination in maize and peanuts. Ultimately, the project aims to develop and scale up biological control technology interventions to improve the health and income of farmers in Sub-Saharan Africa [3]. The Project applies a biocontrol solution developed by the United States Department of Agriculture (USDA) and the Agricultural Research Service (ARS) to reduce AF contamination. Specifically, it uses the ability of native atoxigenic strains of Aspergillus flavus to naturally outcompete their AF-producing cousins [162]. The Partnership for Aflatoxin Control in Africa (PACA) is a collaboration that aims to protect crops, livestock, and people from the effects of AFs. By combating these toxins, PACA will contribute to improve food security, health, and trade across the African continent [3].

The Agricultural Cooperative Development International and Volunteers in Overseas Cooperative Assistance (ACDI/VOCA) project is funded by the USAID and the Bill and Melinda Gates Foundation via the International Institute of Tropical Agriculture (IITA) and the UK government via the African Agricultural Technology Foundation (AATF) [163]. The AATF has been working with the USDA-ARS since 2007 to test the efficacy of Kenyan atoxigenic strains of Aspergillus flavus and training farmers to manage AF [163]. The biocontrol product called AflasafeTM was applied in soil in the Alhaji Sanusi region of Zaria, Nigeria, and a similar product was developed and tested in Kenya and Senegal with encouraging results. AflasafeTM competes with the source of AF, the fungus in the soil, before the fungus can contaminate the crop prior to harvest. AflasafeTM reduces AF contamination in maize and groundnuts by 80-90% and improves the food production, health, livelihood and income of 4.5 million farmers and consumers while also reducing commodity losses due to AF contamination [163].

AFB1-DNA adduct control

Several options to diminish or control AFs and the presence of AFB1-DNA adducts in an organism, which can cause a mutation that may result in carcinogenesis, are presented below. These possibilities include natural repair rates, implicated enzymes, natural products and chemicals.

Natural repair rates of adduct removal

Natural repair rates in the hamster and rat were constant over time with the removal of AFB1-Gua, accounting for the majority of adduct disappearance. Rabbits demonstrated biphasic adduct repair; all types of adducts (AFB1-FAPY) were rapidly removed during the first 12 h after treatment with AFB1, followed by a slower removal phase of primarily AFB1-Gua carcinogen activation. Overall, the repair capabilities of the tracheal epithelium vary among species (rabbit > hamster > rat) [164].

Induction of resistance to AFB1

The induction of resistance to the binding between AFB1 and cellular macromolecules in the rat due to chronic exposure to AFB1 and AFM1 was investigated. Pre-exposure to AFM1 resulted in a small reduction in binding to nucleic acids [165].

Mixtures of genotoxins damage DNA, as evidenced by changes in DNA adduct formation by pre-existing adducts. AFB1-binding to DNA may be altered by conformational changes in the helix due to the presence of a pre-existing acetylamino-fluorene adduct. The use of the chemical probes hydroxylamine and diethylpyrocarbonate render AF ineffective and prevent the local denaturation of the oligomer helix. Changes in the nucleophilicity of neighboring nucleotides and local steric effects cannot be ruled out [166].

Detoxification enzymes

Detoxification enzymes, enzyme inhibition by ß-naphthoflavone (BNF), and CYP450 monooxygenases increased the GST activity by 133% in animals fed 50 μg kg-1 AFB1, by 48% in animals pre-exposed to 50 μg kg-1 AFM1, and remained at control values in rats fed 0.5 μg kg-1 AFM1. BNF is an inducer of various detoxification enzymes, such as CYPs 450 and uridine-5'-diphospho-glucuronosyltransferases (UGTs) [167].

BNF is a chemopreventive agent [168]; it is a flavonoid that occurs in fruits, vegetables, teas, wine, nuts, and seeds. The biological effects of flavonoids include the reduction of cardiovascular disease risk, the inhibition of hepatocytic autophagy, antiviral activity, inhibiting the breakage and disruption of chromosomes (anticlastogenic effects), anti-inflammatory analgesic effects and an anti-ischemic effect [169]. Vitamins (C and E), minerals (zinc, selenium), and plant-based compounds (phenols, flavonoids, isoflavones, and terpenes) act as antioxidants to avoid the formation of fatty plaques in the arteries (anti-atherogenic) and exert anticarcinogenic properties.

Enzyme inhibition can also be used to control AFs: 1) The aryl hydrocarbon (Ah) receptor is a cytosolic protein and activator of transcription that increases the abundance of selective CYP450s, and 2) the ligand is a substance that binds to a specific receptor and triggers a response in the cell. It mimics the action of an endogenous ligand (such as a hormone or neurotransmitter) that binds to the same receptor [170]. Diets containing BNF inhibited in vivo AFB1-DNA adduct formation in 46%. Mechanisms of chemoprevention may depend on the anticarcinogen dose, and even the potent induction of phase I or phase II activities does not assure that a pathway plays a predominantly protective role in vivo [171,172].

BNF inhibits aryl hydrocarbon Ah receptor activation and CYP1A1 activity [173,174]. The induction of detoxification enzymes following chronic exposure to AF might contribute to the reduction of the covalent binding of AFB1 to macromolecules [165].

BNF modulates AFB1 biotransformation in isolated rabbit lung cells [175]. The cytotoxic and carcinogenic mycotoxin AFB1 is biotransformed by CYP450 to a number of relatively nontoxic metabolites as well as to the ultimately toxic metabolite AFBO. In a number of tissues and species, BNF hydroxylates AFB1 to the relatively less toxic metabolite, AFM1.

AF is also toxic and carcinogenic to respiratory tissues. The decrease in AFB1-DNA binding observed in rabbits treated with BNF is apparently due to the selective induction of CYP isozymes and related increases in AFM1 formation and not to the direct inhibition of epoxidation or enhanced conjugation of AFBO with glutathione [175].

Among the members of the mouse CYP450 2A family, CYP450 2A5 is the best catalyst of AFB1 oxidation to its 8,9-epoxide [176].

Recombinant yeasts

The role of amino acid residues 209 and 365 of CYP450 2A5 in the metabolism and toxicity of AFB1 has been studied using recombinant yeasts. In addition, replacing the hydrophobic amino acid at the 365 position with a positively charged lysine residue strongly decreased the metabolism of AFB1. The catalytic parameters of AFB1 generally correlated with its toxicity to the recombinant yeasts expressing the activating enzyme and with the binding of AFB1 to yeast DNA. Furthermore, high-affinity substrates and inhibitors of CYP450 2A5 efficiently blocked the toxicity of AFB1 [176]. The induction of resistance to AFB1 binding to cellular macromolecules in the rat by chronic exposure to AFB1 and AFM1 was also investigated [165].

Pre-exposure to AFM1

Pre-exposure to AFM1 resulted in a small reduction in binding to nucleic acids. In rats pre-exposed to 50 μg kg-1 AFB1, GST activity increased by 133%, and labeled AFB1 binding to DNA, RNA, and protein decreased by 72%, 74%, and 61%, respectively. Binding decreased by 48% in rats pre-exposed to 50 μg kg-1 AFM1, and remained at control values in rats fed 0.5 μg kg-1 AFM1. The induction of detoxification enzymes following chronic exposure to AF might contribute to the reduction in the covalent binding between AFB1 and macromolecules [165].

The AFB1 aldehyde metabolite of AFB1 may contribute to the cytotoxicity of this hepatocarcinogen via protein adduction. AFB1 aldehyde reductases, specifically the NADPH-dependent aldo-keto reductases in the rat (AKR7A1) and human (AKR7A2), are known to metabolize the AFB1 dihydrodiol by forming a AFB1 dialcohol. Using rat AKR7A1 cDNA, a distinct aldo-keto reductase (AKR7A3) from an adult human liver cDNA library was isolated and characterized [177]. The reduced amino acid sequence of AKR7A3 shares 80 and 88% identity with rat AKR7A1 and human AKR7A2, respectively. AKR7A RNA is expressed at various levels in the human liver, stomach, pancreas, kidney and liver. Based on the kinetic parameters determined using recombinant human AKR7A3 and AFB1 dihydrodiol at pH 7.4, the catalytic efficiency of this reaction equals or exceeds those reported for CYP450s and GST, which are known to metabolize AFB1 in vivo. Depending on the extent of AFB1 dihydrodiol formation, AKR7A may contribute to the protection against AFB1-induced hepatotoxicity [177].

Inhibition of AFB1 lesions by different compounds

AFB1-induced tumors or preneoplastic lesions in experimental animals can be inhibited by co-treatment with the compounds described here.

Fischer 344 rats readily develop liver cancer when exposed to AFB1, but the dietary administration of the antioxidant ethoxyquin (EQ) provides protection against hepatocarcinogenesis [178]. Chemoprotection by EQ is accompanied by the overexpression of enzymes that detoxify activated AFB1. AF-protein adducts form following the metabolism of AFB1 to the dialdehydic form of AFB1-dihydrodiol. The dialdehyde can be detoxified by reduction to a dialcohol via the catalytic actions of an enzyme present in the hepatic cytosol from rats fed EQ-containing diets [178].

The enzyme responsible for catalyzing the formation of dihydroxy-AFB1 has been purified from the livers of rats fed diets supplemented with EQ. This enzyme is a soluble monomeric protein, and this inducible enzyme has been designated AFB1-aldehyde reductase (AFB1-AR), a previously unrecognized enzyme that could provide protection against the cytotoxic effects of AFB1 resulting from the formation of protein adducts. The importance of AFB1-AR and the GST Yc2 subunit in conferring resistance to AFB1 has also been discussed [178].

Chemoprevention and protective chemical compounds

Cancer chemoprevention is the use of agents to inhibit, delay or reverse carcinogenesis. Many classes of agents, including anti-estrogens, anti-oxidants, anti-inflammatories, and other diet-derived agents, have shown promise in this context [179]. Some phytochemicals (benzyl isothiocyanate, coumarin, or indole-3-carbinol), synthetic antioxidants, and other drugs (butylated hydroxyanisole, diethyl maleate, ethoxyquin, BNF, Oltipraz, phenobarbital, or trans-stilbene oxide) have been shown to increase hepatic aldo-keto reductase activity toward AFB1-dialdehyde and GST activity toward AFBO in both male and female rats.

Cruciferous vegetables

Several compounds, such as dietary dithiolethione (DTT), glucoraphanin, indole-3-carbinol and Oltipraz, are described below.

Dietary dithiolethiones (DTTs)

DTTs are a class of organosulfur compounds present in cruciferous vegetables. At concentrations of 0.03%, DTTs were demonstrated to potently protect against AFB1 hepatocarcinogenesis, and they also reduced the levels of hepatic AFB1 (AFB)-DNA adducts by 80% following acute or subchronic treatments with AFB (250 μg kg-1 daily) by increasing the hepatic activity of the Phase II enzyme GST without affecting the CYP450 levels or Phase I enzyme activities. The elimination of the major DNA adduct, AFB-Gua, was markedly reduced in animals fed DTT [180].

Cruciferous vegetables (e.g., Brussels sprouts, cabbage) contain several agents, including dithiolethiones, which appear to inhibit carcinogenesis; however, the specific dietary compounds that produce the protective effects have not yet been identified [181].

Brussels sprouts significantly (P< 0.001) decreased hepatic AFB1-DNA binding by 50-60% and increased hepatic and intestinal GST activities [182].

Glucoraphanin, the principal glucosinolate in broccoli sprouts, can be hydrolyzed by gut microflora to sulforaphane, a potent inducer of carcinogen detoxification enzymes. In a randomized, placebo-controlled chemoprevention trial, they demonstrated that drinking hot water infusions of 3-day-old broccoli sprouts, which contained defined concentrations of glucosinolates, altered the presence of AF and phenanthrene. Individuals receiving broccoli sprout glucosinolates exhibited decreased AF-DNA adduct excretion. The effects of glucosinolate-rich broccoli sprouts on urinary levels of AF-DNA adducts and phenanthrene tetraols were reported in a randomized clinical trial in He Zuo township, Qidong, People's Republic of China [183,184].

The inclusion of indole-3-carbinol (I3C), a component of cruciferous vegetables, in experimental diets inhibited in vivo AFB1-DNA adduct formation in 68%, and the addition of BNF (dexamethasone, a corticosteroid) further increased this inhibition to 51% [171]. AFB1-induced tumors or preneoplastic lesions can be inhibited in experimental animals by cotreatment with several compounds, including I3C and the well-known Ah receptor agonist BNF. This study examines the influence of these two agents on the AFB1-glutathione detoxification pathway and AFB1-DNA adduction in rat livers [171].

Oltipraz [5- (2-pyrazinyl)- 4-methyl-1, 2-dithiole-3-thione; RP 35972] is a synthetic, substituted 1,2-dithiole-3-thione previously used in humans as an antischistosomal agent. Animal studies have demonstrated that Oltipraz is a potent inducer of Phase II detoxification enzymes, most notably GST. Dietary concentrations of Oltipraz markedly inhibit AFB1-induced hepatic tumorigenesis in rats. The levels of hepatic AF-DNA adducts, urinary AF-N7-guanine, and serum AF-albumin adducts decreased when the biliary elimination of AF-glutathione conjugants increased, thus providing predictive biomarkers that can be used to measure a chemopreventive effect. In other animal experiments, Oltipraz was found to inhibit chemically induced carcinogenesis in bladder, colon, breast, stomach, and skin cancer models. In addition, Oltipraz has been shown to be non-mutagenic and act as a radioprotector and chemoprotective agent against carbon tetrachloride and acetaminophen toxicity [181].

Oltipraz protects against AFB1-induced hepatocarcinogenesis in rats when fed before and during carcinogen exposure; however, this type of exposure-chemoprotection is not directly relevant to most human populations. GST catalyzes the detoxification of AFBO and was found to be rapidly induced in the livers of animals after the beginning of Oltipraz intervention. The significant protection against presumptive preneoplastic tumors suggests that Oltipraz may substantially inhibit the cytotoxic and autopromoting action of repeated exposure to AFB1 and support the utility of intervention trials with Oltipraz in individuals chronically consuming AFB1-contaminated foods, particularly in regions with high incidences of liver cancer [185]. Oltipraz was reported as a useful agent for the modulation of gene expression in subjects at risk for colorectal cancer [186].


Butylated hydroxytoluene (BHT) and ellagic acid (EA) are described below.

Butylated hydroxytoluene (BHT): Also known as dibutylhydroxytoluene, BHT is a lipophilic organic derivative of phenol that exhibits antioxidant properties. Specifically, BHT inhibits tumor formation due to AFB1 by inducing liver GSH-S-transferases. The permitted dose of BHT, added to processed food as a preservative, does not affect the biotransformation of AFB1 [187]. The effects of low- and high-dose dietary BHT on microsome-mediated AFB1-DNA binding were compared [187].

The anticarcinogenic effect of BHT pretreatment on the metabolism and genotoxicity of AFB1 in primary cultures of rat hepatocytes was due to hepatic detoxification mechanisms. Specifically, the intracellular concentrations of reactive metabolites were reduced, and fewer covalently bound adducts were formed [188].

Ellagic acid (EA), a plant phenol found in various fruits, raspberries and nuts, was examined for its ability to inhibit AFB1 mutagenesis and DNA damage in cultured rat and human tracheobronchial tissues [189]. In the presence of a rat liver S9 microsomal preparation, EA (1.5 μg/plate) inhibited the number of mutations induced by AFB1 (0.5 μg/plate) by 50%. EA at a dose of 1000 μg/plate inhibited the mutation frequency > 90%. In tissues, the major AFB1- DNA adducts were AFB1-Gua and AFB1–FAPY, and their formation was reduced by 28-76% in the presence of EA. EA acts as a naturally occurring inhibitor of AFB1-related respiratory damage in rats and humans [189].


Indomethacin is a nonsteroidal anti-inflammatory drug that produced a 63-100% decrease in [3H] AFB1-DNA binding in macrophages from five of seven patients, whereas nordihydroguaiaretic acid inhibited [3H] AFB1-DNA adduct formation by 19, 40 and 56% in macrophages from three of seven patients [190].


Selenium effectively inhibited AFB1-induced DNA damage, exerting a anticarcinogenic effect against AFB1. Selenium pretreatment inhibited AFB1-DNA binding and adduct formation by increasing the level of reduced GSH in the liver of treated animals [191].

Natural nutrients

The medicinal herb Thonningia sanguinea, which is prophylactically used against bronchial asthma in Ghana, exhibits antioxidative and hepatoprotective actions against acute AFB1 hepatotoxicity in Fischer 344 rats [192].

Coumarin chemoprevention

Coumarin is a natural benzopyrone that is a potent inducer of AFB1-aldehyde reductase, the GST A5 and P1 subunits, and NAD(P) H:quinone oxidoreductase in the rat liver [193]. The consumption of a coumarin-containing diet provides substantial protection against the initiation of AFB1 hepatocarcinogenesis in the rat [193].

Cafestol and kahweol (C&K)

These diterpenes are two potentially chemoprotective agents present in green and roasted coffee beans; they act as blocking agents by modulating multiple enzymes involved in carcinogen detoxification [194]. Significant inhibition was detected at 2300 mg kg-1, and the reduction of DNA adduct formation to nearly 50% of the control value was maximized by 6200 mg kg-1 of dietary C&K. Two complementary mechanisms may account for the chemopreventive action of cafestol and kahweol against AFB1 in rats. A decrease in the expression of the rat activating CYP450s (CYP2C11 and CYP3A2) was observed, which was accompanied by a strong induction of the expression of the GST subunit GST Yc2, which detoxifies AFB1. These coffee components may broadly inhibit chemical carcinogenesis [194].


A potent protection against AF-induced tumorigenesis through induction of Nrf2-regulated pathways by the triterpenoid 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl] imidazole was reported [195].


Salvia, amaranth seeds and eucalyptus reduced adduct formation in rats exposed to AFB1 [196].


The influence of grapefruit juice intake on AFB1-induced liver DNA damage was examined in F344 rats administered 5 mg kg-1 AFB1 by gavage. Grapefruit juice extract inhibited AFB1-induced mutagenesis by inhibiting the metabolic activation potency of AFB1 in the rat liver [197].

The hepatic GST activity and glutathione content in the portal blood and the liver concentrations of AFB1 did not significantly differ between grapefruit juice intake rats and the controls, but fewer revertant colonies were observed in the Ames test using Salmonella typhimurium TA98. A significant decrease in the hepatic CYP3A content, but not the CYP1A and CYP2C contents, was observed in the microsomes of grapefruit juice-treated rats compared with non-treated rats [197].


Whereas lycopene and an excess of vitamin A showed no effect, ß-carotene, ß-apo-8'carotenal, astaxanthin and canthaxanthin, and a highly carcinogenic polycyclic aromatic hydrocarbon called 3 methylcholanthreno (3-MC) were highly efficient in reducing the number and size of liver preneoplastic foci [198].

Both ß carotenoids and 3-MC decreased AFB1-induced DNA single-strand binding protein and the binding of AFB1 to liver DNA and plasma albumin in vivo. In vitro, these compounds increased AFB1 metabolism to AFM1, a less genotoxic metabolite. These carotenoids exert their protective effect by directing AFB1 metabolism towards detoxification pathways. By contrast, ß-carotene did not protect hepatic DNA from AFB1-induced alteration, and caused only minor changes in AFB1 metabolism. Thus, its protective effect against the initiation of liver preneoplastic foci by AFB1 appears to be mediated by other mechanisms [198]. The intake of 300 mg of ascorbic acid by gavage protected guinea pigs from the acute toxicity of AFB1 [199].

Finally, human hepatocytes (HepG2) cells pretreated with lycopene and ß-carotene are protected from the toxic effects of AFB1 at both the cellular and molecular levels [200].

Oldenlandia diffusa and Scutellaria barbata

Oldenlandia diffusa and Scutellaria barbata have been used in traditional Chinese medicine to treat liver, lung and rectal tumors. They inhibited mutagenesis, DNA binding and the metabolism of AFB1 bioactivation [201]. Specifically, they exerted antimutagenic and antitumorigenic effects on AFB1 by inhibiting the CYP3-mediated metabolism of AFB1 [201].

Oldenlandia diffusa (=Hedyotis diffusa) is from the Rubiaceae family, found in the southeastern provinces of China-Guangxi, Guangdong and Fujian-growing at low altitude in moist fields. It is dried in sunlight to make tea or used fresh. The part of the plant used in herbal formulas is the rhizome. An early use of this herb was to treat poisonous snake bites, to cure childhood malnutrition, acute appendicitis, peritonitis and cancer tumors, especially from stomach, esophagus, rectum, ovary, pleura, liver and lung and, when used externally, it is effective for vesicles and ichthyosis. It is bitter, neutral, non-toxic, and used to clear heat, remove toxin, and alleviate pain [202-210].

Scutellaria barbata

Scutellaria barbata is a species of flowering plant in the mint family, Lamiaceae. It is native to Asia. Its English common name is barbed skullcap.

Scutellaria refers to banzhilian, the whole plant of Scutellaria barbata, and should not be confused with "scute," the common name referring to huangqin, the root of Scutellaria baicalensis. These are in the mint family. Though both are from the same genus, the former, for which the tops are used, has essential oils among the active components, while the latter relies primarily on flavonoids, particularly baicalin and baicalein [211-214].

The Chinese name for the herb refers to "half twigs" (banzhi): the stems of the plant are half covered with leaves and half a flower stalk, hence the name. The term lian is used to describe the lotus, which is most likely mentioned here just to indicate that the plant is valued, not for any other relation. Scutellaria had been used as a folk medicine and is not mentioned in any classic herbals. It was first described formally in a modern science journal (Jiangsu Botanicals Journal). It was reported in the National Collection of Medicinal Herbs that: "the herb is slightly bitter and cool, used to clear heat, remove toxin, and vitalize blood to remove blood stasis, and it has anticancer actions; it is used for tumor, appendicitis, hepatitis, ascites due to cirrhosis, and pulmonary abscess."[211-214].

The plant is a small-leaved mint, producing bright purple flowers. Like Oldenlandia, it grows in moist flatlands, particularly at the edges of rice paddies and ditches, in southeastern China, though it is also found further West, to Sichuan, and further north, to Shaanxi, and at altitudes up to 2,000 feet. The tops are collected in late spring or early June, and carefully dried.

Scutellaria is much less studied than Oldenlandia, so there is only limited information available about it. However, it is considered of potential value and has been shown in laboratory studies to provide some of the same mechanisms of anticancer action as Oldenlandia mentioned above [211-214]. It is a common practice to combine it with Oldenlandia, especially for treatment of cancer, though it is sometimes used alone or with other herbs.

Anti-Cancer Formulations

In the book Anticancer Medicinal Herbs, some therapies are mentioned with Oldenlandia and Scutellaria as main ingredients for cancers of the specified areas as indicated below. The listing by cancer site is what the formula had been applied for at the hospital where it was being used:

Stomach: Combine Oldenlandia (90 g) and Imperata (60 g) or use Scutellaria (30) and Imperata (30).

Esophagus, rectum, and stomach: Oldenlandia (70 g) and Coix lacryma-jobi (30 g); plus other herbs in small quantities.

Esophagus: Oldenlandia (60 g), Scutellaria (60 g), Cycas leaf (60 g), Imperata (60 g), cotton root (60 g).

Rectum: Oldenlandia (60 g), Scutellaria (15 g), Solanum (60 g), lonicera stem (60 g), Viola (15 g).

Ovary: Oldenlandia (30 g), Scutellaria (50 g), Solanum (50 g S. nigri; 30 g S. lyrati), turtle shell (30 g).

Pleura (metastasize to): Scutellaria (120 g), Taraxacum (30 g)

Liver, rectum, lung: Oldenlandia (60 g) and Scutellaria (60 g)

Liver: Oldenlandia (60 g), Scutellaria (60 g), Cycis (18 g), Phragmites (30 g) [211-214].


Chlorophyllin is another natural product that has been reported as useful to reduce aflatoxin-DNA adducts in individuals at high risk for liver cancer [215].

Probiotic bacteria

Some selected strains of probiotic bacteria can form tight complexes with AFB1 and other carcinogens and can block the intestinal absorption of AFB1 to reduce the urinary excretion of AFB1-Gua, a marker of the biologically effective dose of AF exposure. Increases in the urinary excretion of AFB1-Gua adduct are associated with an increased risk of liver cancer. A probiotic supplement has been shown to reduce the biologically effective dose of AF exposure and may thereby offer an effective dietary approach to decrease the risk of liver cancer [216].

Additives: Aluminosilicates and glucomannans

The most frequently used method to decontaminate grains for feed are the addition of aluminosilicates, zeolites and glucomannans. Aluminosilicates are oxides of silicon and aluminum associated with cations, such as calcium, magnesium, sodium, potassium, etc. The dosage for synthetic aluminosilicates is 1 kg/ton, and the dosage for natural aluminosilicates is 3 to 5 kg/ ton of feed [217]. Glucomannan comprises 40% of the dry weight of the roots of the Konjac plant, and it is also a constituent of the bacterial, plant and yeast cell walls, where it differs in the branches or glycosidic linkages in the linear structure [218-220].


AFs are highly regulated worldwide, with strict limits permitted in human commodities and animal feed.

The current worldwide regulations for AFs vary depending on whether the country setting the limits is an importer or exporter. In 76 countries, the AFt tolerance limits are 0-35 μg kg-1, whereas 61 countries legislate AFB1 to be between 1-20 μg kg-1 [221].

The European Union legislated the level of AFB1 and AFt in corn to be 5 μg kg-1 and 10 μg kg-1, respectively, for further treatment [222].

The Food and Drug Administration (FDA) analyzes products via a formal compliance program and exploratory surveillance activity [30]. The FDA regulatory levels for AFt (μg kg-1) apply 20 μg kg-1 to all products for humans, except for milk; the limit for corn for immature animals and dairy cattle is 20 μg kg-1; the limit for corn or peanuts for breeding beef cattle, swine and mature poultry is 100 μg kg-1; the limit for corn or peanuts for finishing swine is 200 μg kg-1; the limit for corn or peanuts for finishing beef cattle is 300 μg kg-1; the limit for cotton seed meal as a feed ingredient is 300 μg kg-1; the limit of all other feed stuffs is 20 μg kg-1, and that for milk (AFM1) is 0.5 μg kg-1 [222].


Although aflatoxins are “unavoidable” toxins in food, and the most important mutagens and carcinogens due to their frequent ingestion and the big amount of contaminated foods, many methods are available to control them, ranging from natural detoxifying methods to more sophisticated ones. The metabolic routes of aflatoxins were mentioned here, including the CYP 450 isoenzymes and the formation of biomarkers. Physicians must be well informed to help people with uncommon and easy ways to control aflatoxins, which have produced serious outbreaks worldwide. The easy ways can be to reduce the ingestion of risky foods such as oilseeds, dairy products, spices, chili pepper and dry fruits, to prefer wheat instead of maize products. In the field the biocontrol method using non mutagenic Aspergillus spp strains have given good results. The role of government is crucial in monitoring the food products that are available for the human population, as well as the importations of foods with undetectable amounts of aflatoxins.


The author thanks to IBUNAM personnel: Noemí Chávez, from the Technical Secretary (Secretaría Técnica); Joel Villavicencio, Jorge López, Alfredo Wong, and Julio César Montero for computer assistance; Georgina Ortega Leite and Gerardo Arévalo for library information.


  1. Food and Agriculture Organization (FAO) (2004) Food and Agriculture Organization of the United Nations. Worldwide regulations for mycotoxins in food and feed in 2003. Food and Nutrition Paper, No. 81. FAO, Rome, Italy.
  2. Smith JE, Solomons GL, Lewis CW, Anderson JG (1994) Mycotoxins in Human Nutrition and Health. Brussels: European Commission CG XII.
  3. Centers for Disease Control and Prevention (CDC) (2004) Outbreak of aflatoxin poisoning--eastern and central provinces, Kenya, January-July 2004. MMWR Morb Mortal Wkly Rep 53: 790-793.
  4. Bhat RV, Krishnamachari KA (1977) Follow-up study of aflatoxic hepatitis in parts of western India. Indian J Med Res 66: 55-58.
  5. Jaimez J, Fente CA, Vazquez BI, Franco CM, Cepeda A, et al. (2000) Application of the assay of aflatoxins by liquid chromatography with fluorescence detection in food analysis. J Chromatogr A 882: 1-10.
  6. Leeson S, Diaz G, Summers J (1995) Poultry metabolic disorders and mycotoxins. University Books, Ontario, Canada.
  7. Palmgren MS, Hayes AW (1987) Aflatoxins in Food. In: Mycotoxins in foods. Food Science and Technology, A Series of monographs Ed Academic Press. San Diego, USA.
  8. Nakai VK, Rocha LO, Gonçalez E, Fonseca H, Ortega EMM, et al. (2008) Distribution of fungi and aflatoxins in a stored peanuts variety. Food Chem 106: 285-290.
  9. Rastogi SC, Heydorn S, Johansen JD, Basketter DA (2001) Fragrance chemicals in domestic and occupational products. Contact Dermatitis 45: 221-225.
  10. Akiyama H, Goda Y, Tanaka T, Toyoda M (2001) Determination of aflatoxins B1, B2, G1 and G2 in spices using a multifunctional column clean-up. J Chromatogr A 932: 153-157.
  11. Lindner E (1995) Foods Toxicology (2nd edn). Acribia SA Zaragoza, Spain.
  12. Otta KH, Papp E, Bagócsi B (2000) Determination of aflatoxins in food by overpressured-layer chromatography. J Chromatogr A 882: 11-16.
  13. Williams J, Wilson D (1999) Report about the aflatoxin problem in chesnut (Bertholletiaexcelsa) in Bolivia: Technical Document 71: 4-7.University of Georgia, USAID/Bolivia.
  14. Derache J (1990) Toxicology and Food Safety, Omega. Barcelona, Spain pp. 73-88.
  15. Proctor AD, Ahmedna M, Kumar JV, Goktepe I (2004) Degradation of aflatoxins in peanut kernels/flour by gaseous ozonation and mild heat treatment. Food AdditContam 21: 786-793.
  16. Sweeney MJ, Dobson AD (1999) Molecular biology of mycotoxin biosynthesis. FEMS Microbiol Lett 175: 149-163.
  17. Eaton D, Groopman J (1994) The Toxicology of Aflatoxins: Human Health, Veterinary and Agricultural Significance. Academic Press: San Diego, CA.
  18. Trail F, Mahanti N, Linz J (1995) Molecular biology of aflatoxin biosynthesis. Microbiology 141 : 755-765.
  19. Minto RE, Townsend CA (1997) Enzymology and Molecular Biology of Aflatoxin Biosynthesis. Chem Rev 97: 2537-2556.
  20. Bennett JW, Chang PK, Bhatnagar D (1997) One gene to whole pathway: the role of norsolorinic acid in aflatoxin research. Adv Appl Microbiol 45: 1-15.
  21. OPS, Panamerican Health Organization (1983) Criteria of Environmental Health 11. Scientific Publication N° 453. World Health Organization, Washington, USA.
  22. Reddy SV, Farid W (2006 a) Properties of aflatoxin and it producing fungi.
  23. Rustom IYS, López-Leiva MH, Nair BM (1993) Effect of pH and heat treatment on the mutagenic activity of peanut beverage contaminated with aflatoxin. Food Chem 46: 37-42.
  24. Rustom IYS (1997) Aflatoxin in Food and Feed: Occurrence, legislation and inactivation by physical methods. Food Chem 59: 57-67.
  25. Price RL, Jorgensen KV (1985) Effects of processing on aflatoxins levels and on mutagenic potential of tortillas made from naturally contaminated corn. J Food Sci 50: 347-349.
  26. Moctezuma-Zárate MG, Carvajal M, Espinosa-Aguirre JJ, Gonsebatt-Bonaparte ME, Rojo-Callejas F, et al. (2015) Role of pH in the mutagenicity of Aflatoxin B1 in maize tortillas during in vitro human digestion model. J Food Nutr Disord 4: 3-13.
  27. Holcomb M, Wilson DM, Trucksess MW, Thompson HC Jr (1992) Determination of aflatoxins in food products by chromatography. J Chromatogr 624: 341-352.
  28. Link HF (1809) Observationes in Ordinesplantarumnaturales. Dissertatio prima, complectensAnandrarumordinesEpiphytas, MucedinesGastomycos et Fungos Der GesellschaftNaturforschenderFreundezu Berlin. Magazinf?r die neuestenEntdeckungen in der gesamtenNaturkunde 3: 1-42.
  29. Scheidegger KA, Payne GA (2003) Unlocking the secrets behind secondary metabolism: A review of Aspergillus flavus from pathogenicity to functional genomics. J Toxicol-Toxin Rev 22: 423-459.
  30. Richard JL, Payne GA (2003) Mycotoxins: Risks in plant, animal, and human systems. Task Force Report No. 139. Council for Agric Sci Technol, USA.
  31. Payne GA (1998) Process of contamination by aflatoxin producing fungi and their impacts on crops. In: Mycotoxins in Agriculture and Food Safey. Sinha KK and Bhatnagar D. Marcel (eds). Dekker, Inc, New York, USA.
  32. Speare AT (1912) Fungi parasitic upon insects injurious to sugar cane. Pathology and Physiological Series, Bulletin No. 12. Honolulu: Hawaiian Sugar Planters’ Assoc Exp Stat. Path Phys. Series Bull 12: 1-62.
  33. Cullen JM, Newberne PM (1994) Acute hepatotoxicity of aflatoxins. In: Eaton DL, Groopman JD (eds.) The toxicology of aflatoxins: human health, veterinary, and agricultural significance.
  34. Horn BW, Greene RL, Sobolev VS, Dorner JW, Powell JH, et al. (1996) Association of morphology and mycotoxin production with vegetative compatibility groups in Aspergillus flavus, A. parasiticus, and A. tamarii. Mycologia 88: 574-587.
  35. Horn BW, Greene RL (1995) Vegetative compatibility within populations of Aspergillus flavus, A. parasiticus, and A. tamarii from a peanut field. Mycologia 87: 324-332.
  36. McAlpin CE, Wicklow DT, Platis CE (1998) Genotypic diversity of Aspergillus parasiticus in an Illinois corn field. Plant Dis 82: 1132-1136.
  37. Geiser DM, Timberlake WE, Arnold ML (1996) Loss of meiosis in Aspergillus. Mol Biol Evol 13: 809-817.
  38. Peterson SW (2008) Phylogenetic analysis of Aspergillus species using DNA sequences from four loci. Mycologia 100: 205-226.
  39. Klich MA, Pitt JI (1988) Differentiation of Aspergillus flavus from A. parasiticus and other closely related species. Trans Brit Mycol Soc 91: 99-108.
  40. Kurtzman CP, Horn BW, Hesseltine CW (1987) Aspergillus nomius, a new aflatoxin-producing species related to Aspergillus flavus and Aspergillus tamarii. Antonie Van Leeuwenhoek 53: 147-158.
  41. Horn BW, Moore GG, Carbone I (2011) Sexual reproduction in aflatoxin-producing Aspergillus nomius. Mycologia 103: 174-183.
  42. Goto T, Wicklow DT, Ito Y (1996) Aflatoxin and cyclopiazonic acid production by a sclerotium-producing Aspergillus tamarii strain. Appl Environ Microbiol 62: 4036-4038.
  43. Domsch KH, Gams W, Anderson TH (1980) Compendium of soil fungi. Academic Press, UK. pp. 865.
  44. OPS, Panamerican Health Organization (2002) Health in the Americas. Vol. II. Technical Scientific Publication N° 587. World Health Organization, Washington, USA.
  45. Castillo-Urueta P, Carvajal M, Méndez I, Meza F, Gálvez A (2011) Survey of aflatoxins in maize tortillas from Mexico City. Food AdditContam Part B Surveill 4: 42-51.
  46. Suárez-Bonnet E, Carvajal M, Méndez-Ramírez I, Castillo-Urueta P, Cortés-Eslava J, et al. (2013) Aflatoxin (B1 , B2 , G1 , and G2 ) contamination in rice of Mexico and Spain, from local sources or imported. J Food Sci 78: T1822-1829.
  47. Rosas Contreras C (2014) Comparative study, identification, and quantification of the mutagenic and carcinogenic fungal toxins called aflatoxins, in hot pepper (Capsicum spp. L.) of Mexico. BSc Thesis in Food Chemistry. Chemistry Faculty, National Autonomous University of Mexico, UNAM.
  48. Carvajal M, Bolaños A, Rojo F, Méndez I (2003) Aflatoxin M1 in pasteurized and ultrapasteurized milk with different fat content in Mexico. J Food Prot 66: 1885-1892.
  49. Carvajal M, Rojo F, Méndez I, Bolaños A (2003) Aflatoxin B1 and its interconverting metabolite aflatoxicol in milk: the situation in Mexico. Food AdditContam 20: 1077-1086.
  50. Falcón Campos LP (2013) Identificación y cuantificación de aflatoxinas y susmetabolitoshidroxilados del alimento al huevo de gallinapor HPLC. BSc Thesis in Food Chemistry. Chemistry Faculty, National Autonomous University of Mexico, UNAM.
  51. Díaz-Zaragoza M, Carvajal-Moreno M, Méndez-Ramírez I, Chilpa-Galván NC, Avila-González E, et al. (2014) Aflatoxins, hydroxylated metabolites, and aflatoxicol from breast muscle of laying hens. Poult Sci 93: 3152-3162.
  52. Moreno OJ, Kang MS (1999) Aflatoxins in Maize: The Problem and Genetic Solutions. Plant Breeding 118:1-16.
  53. International Agency for the Research on Cancer (IARC) (1993) Some naturally occurring substances: Food items and constituents, heterocyclic aromatic amines and mycotoxins. IARC Monographs on the evaluation of carcinogenic risks to humans 56: 245.
  54. IARC Working Group on the Evaluation of Carcinogenic Risks to Humans (2002) Some traditional herbal medicines, some mycotoxins, naphthalene and styrene. IARC MonogrEval Carcinog Risks Hum 82: 1-556.
  55. Fung F, Clark RF (2004) Health effects of mycotoxins: a toxicological overview. J Toxicol Clin Toxicol 42: 217-234.
  56. Olsen JH, Dragsted L, Autrup H (1988) Cancer risk and occupational exposure to aflatoxins in Denmark. Br J Cancer 58: 392-396.
  57. Turner PC, Moore SE, Hall AJ, Prentice AM, Wild CP (2003) Modification of immune function through exposure to dietary aflatoxin in Gambian children. Environ Health Perspect 111: 217-220.
  58. Ross RK, Yuan JM, Yu MC, Wogan GN, Qian GS, et al. (1992) Urinary aflatoxin biomarkers and risk of hepatocellular carcinoma. Lancet 339: 943-946.
  59. Wogan GN (1992) Aflatoxins as risk factors for hepatocellular carcinoma in humans. Cancer Res 52: 2114s-2118s.
  60. Shank RC, Bourgeois CH, Keschamras N, Chandavimol P (1971) Aflatoxins in autopsy specimens from Thai children with an acute disease of unknown aetiology. Food Cosmet Toxicol 9: 501-507.
  61. Chao TC, Maxwell SM, Wong SY (1991) An outbreak of aflatoxicosis and boric acid poisoning in Malaysia: a clinicopathological study. J Pathol 164: 225-233.
  62. Patten RC (1981) Aflatoxins and disease. Am J Trop Med Hyg 30: 422-425.
  63. Krishnamachari KA, Bhat RV, Nagarajan V, Tilak TB (1975) Hepatitis due to aflatoxicosis. An outbreak in Western India. Lancet 1: 1061-1063.
  64. Peraica M, Radic B, Lucic A, Pavlovic M (1999) Toxic effects of mycotoxins in humans. Bull World Health Organ 77: 754-766.
  65. Gong YY, Hounsa A, Egal S, Turner PC, Sutcliffe AE, et al. (2004) Postweaning exposure to aflatoxin results in impaired child growth: a longitudinal study in Benin, West Africa. Environ Health Perspect 112: 1334-1338.
  66. Dean JH, Luster MI, Munson AE, Kimber I (1994) Immunotoxicology and Immunopharmacology. Raven Press, New York USA.
  67. Pestka JJ, Bondy GS (1994) Mycotoxin-induced immune modulation, In: Dean JH, Luster MI, Munson AE, Kimber I (eds). Immunotoxicology and Immunopharmacology. Raven Press, New York, USA.
  68. Denning DW (1987) Aflatoxin and human disease. Adverse Drug React Acute Poisoning Rev 6: 175-209.
  69. Llewellyn GC, Stephenson GA, Hofman JW (1977) Aflatoxin B1 induced toxicity and teratogenicity in japaneseMedaka eggs (Oryziaslatipes). Toxicon 15: 582-587.
  70. Krishnamachari KA, Bhat RV, Nagarajan V, Tilak TB (1975) Investigations into an outbreak of hepatitis in parts of western India. Indian J Med Res 63: 1036-1049.
  71. Reye RD, Morgan G, Baral J (1963) Encephalopathy and Fatty Degeneration of the Viscera. A Disease Entity in Childhood. Lancet 2: 749-752.
  72. Apeagyei F, Lamplugh SM, Hendrickse RG, Affram K, Lucas S (1986) Aflatoxins in the livers of children with kwashiorkor in Ghana. Trop Geogr Med 38: 273-276.
  73. Azziz-Baumgartner E, Lindblade K, Gieseker K, Rogers HS, Kieszak S, et al. (2005) Case-control study of an acute aflatoxicosis outbreak, Kenya, 2004. Environ Health Perspect 113: 1779-1783.
  74. Ngindu A, Johnson BK, Kenya PR, Ngira JA, Ocheng DM, et al. (1982) Outbreak of acute hepatitis caused by aflatoxin poisoning in Kenya. Lancet 1: 1346-1348.
  75. Centers for Disease Control and Prevention (CDC) (2004) Outbreak of aflatoxin poisoning--eastern and central provinces, Kenya, January-July 2004. MMWR Morb Mortal Wkly Rep 53: 790-793.
  76. Lewis L, Onsongo M, Njapau H, Schurz-Rogers H, Luber G, et al. (2005) Aflatoxin contamination of commercial maize products during an outbreak of acute aflatoxicosis in eastern and central Kenya. Environ Health Perspect 113: 1763-1767.
  77. Autrup H, Bradley KA, Shamsuddin AKM, Wakhisi J, Wasunna A (1983) A detection of putative adduct with fluorescence characteristics identical to 2,3-dihydro-2-(7'-guanyl)-3-hydroxyaflatoxin B1 in human urine collected in Muranga District, Kenya. Carcinogenesis (Lond.) 4: 1193-1195.
  78. Oyelami OA, Maxwell SM, Adelusola KA, Aladekoma TA, Oyelese AO (1997) Aflatoxins in the lungs of children with kwashiorkor and children with miscellaneous diseases in Nigeria. J Toxicol Environ Health 51: 623-628.
  79. Kirk GD, Lesi OA, Mendy M, Akano AO, Sam O, et al. (2004) The Gambia Liver Cancer Study: Infection with hepatitis B and C and the risk of hepatocellular carcinoma in West Africa. Hepatology 39: 211-219.
  80. Kaaya NA, Warren HL (2005) A review of past and present research on aflatoxin in Uganda. AJFAND 5: 1-18.
  81. Kitya D, Bbosa GS, Mulogo E (2010) Aflatoxin levels in common foods of South Western Uganda: a risk factor to hepatocellular carcinoma. Eur J Cancer Care (Engl) 19: 516-521.
  82. Hendrickse RG, Coulter JB, Lamplugh SM, MacFarlane SB, Williams TE, et al. (1983) Aflatoxins and kwashiorkor. Epidemiology and clinical studies in Sudanese children and findings in autopsy liver samples from Nigeria and South Africa. Bull Soc Pathol ExotFiliales 76:559-566.
  83. Peers FG, Gilman GA, Linsell CA (1976) Dietary aflatoxins and human liver cancer. A study in Swaziland. Int J Cancer 17: 167-176.
  84. Peers F, Bosch X, Kaldor J, Linsell A, Pluijmen M (1987) Aflatoxin exposure, hepatitis B virus infection and liver cancer in Swaziland. Int J Cancer 39: 545-553.
  85. Van Rensburg SJ, van der Watt JJ, Purchase IF, Pereira Coutinho L, Markham R (1974) Primary liver cancer rate and aflatoxin intake in a high cancer area. S Afr Med J 48: 2508A-2508D.
  86. Van Rensburg SJ, Cook-Mozaffari P, Van Schalkwyk DJ, Van der Watt JJ, Vincent TJ, et al. (1985) Hepatocellular carcinoma and dietary aflatoxin in Mozambique and Transkei. Br J Cancer 51: 713-726.
  87. Shank RC, Gordon JE, Wogan GN (1972) Dietary aflatoxins and human liver cancer. III. Field survey of rural Thai families for ingested aflatoxin. IV. Incidence of primary liver cancer in two municipal populations of Thailand. Food Cosmet Toxicol 10:71-84.
  88. Lye MS, Ghazali AA, Mohan J, Alwin N, Nair RC (1995) An outbreak of acute hepatic encephalopathy due to severe aflatoxicosis in Malaysia. Am J Trop Med Hyg 53: 68-72.
  89. Groopman JD, Cain LG, Kensler TW (1988) Aflatoxin exposure in human populations: measurements and relationship to cancer. Crit Rev Toxicol 19: 113-145.
  90. Groopman JD, Zhu JQ, Donahue PR, Pikul A, Zhang LS, et al. (1992) Molecular dosimetry of urinary aflatoxin-DNA adducts in people living in Guangxi Autonomous Region, People's Republic of China. Cancer Res 52: 45-52.
  91. Qian GS, Ross RK, Yu MC (1994) A follow-up study of urinary markers of aflatoxin exposure and liver cancer risk in Shanghai, Peoples Republic of China. Cancer Epidemiol Biomarkers Prevent 3: 3-10.
  92. Scholl P, Groopman JD. (1995) Epidermiology of human exposures and its relationship to liver cancer. In: Eklund M, Richard JL, Mise K. (eds.). Molecular Approaches to Food Safety: Issues Involving Toxic Microorganisms. Alaken, Inc., Fort Collins, Co.
  93. Wang LY, Hatch M, Chen CJ, Levin B, You SL, et al. (1996) Aflatoxin exposure and risk of hepatocellular carcinoma in Taiwan. Int J Cancer 67: 620-625.
  94. Jelinek CF (1987) Distribution of mycotoxins -An analysis of worldwide commodities data, including data from FAO/WHO/UNEP food contamination monitoring programme. Joint FAO/WHO/UNEP 2nd International Conference on Mycotoxins, Bangkok, Thailand.
  95. Denning DW, Quiepo SC, Altman DG, Makarananda K, Neal GE, et al. (1995) Aflatoxin and outcome from acute lower respiratory infection in children in The Philippines. Ann Trop Paediatr 15: 209-216.
  96. Williams JH, Phillips TD, Jolly PE, Stiles JK, Jolly CM, et al. (2004) Human aflatoxicosis in developing countries: a review of toxicology, exposure, potential health consequences, and interventions. Am J Clin Nutr 80: 1106-1122.
  97. Food and Drug Administration (FDA) (2012) Bad Bug Book: Foodborne pathogenic microorganisms and natural toxins handbook. Aflatoxins Accessed Sept 2, 2015.
  98. Lamb DC, Lei L, Warrilow AG, Lepesheva GI, Mullins JG, et al. (2009) The first virally encoded cytochrome p450. J Virol 83: 8266-8269.
  99. Aoyama T, Yamano S, Guzelian PS, Gelboin HV, Gonzalez FJ (1990) Five of 12 forms of vaccinia virus-expressed human hepatic cytochrome P450 metabolically activate aflatoxin B1. Proc Nati Acad Sci 87: 4790-4793.
  100. Ding X, Kaminsky LS (2003) Human extrahepatic cytochromes P-450: Function in xenobiotic metabolism and tissue-selective chemical toxicity in the respiratory and gastrointestinal tracts. Annu Rev Pharmacol Toxicol 43: 149-173.
  101. Shimada T, Yamazaki H, Mimura M, Inui Y, Guengerich FP (1994) Interindividual variations in human liver cytochrome P-450 enzymes involved in the oxidation of drugs, carcinogens and toxic chemicals: Studies with liver microsomes of 30 japaneses and 30 caucasians. J Pharm Exp Ther 270: 414-423.
  102. Bbosa GS, Kitya D, Odda J, Ogwal-Okeng J (2013) Aflatoxins metabolism, effects on epigenetic mechanisms and their role in carcinogenesis. Health 5: 14-34.
  103. Pelkonen P, Lang MA, Negishi M, Wild CP, Juvonen RO (1997) Interaction of aflatoxin B1 with cytochrome P450 2A5 and its mutants: correlation with metabolic activation and toxicity. Chem Res Toxicol 10: 85-90.
  104. Shimada T, Hayes CL, Yamazaki H, Amin S, Hecht SS, et al. (1996) Activation of chemically diverse procarcinogens by human cytochrome P-450 1B1. Cancer Res 56: 2979-2984.
  105. Shimada T, Oda Y, Gillam EMJ, Guengerich FP, Inoue K (2001) Metabolic activation of polycyclic aromatic hydrocarbons and other procarcinogens by cytochromes P450 1A1 and P450 1B1 allelic variants and other human cytochromes P450 in Salmonella typhimurium NM2009. Drug Metab Dispos 29: 1176–1182.
  106. Guengerich FP, Shimada T (1991) Oxidation of toxic and carcinogenic chemicals by human cytochrome P-450 enzymes. Chem Res Toxicol 4: 391-407.
  107. Jaiswal AK, Nebert DW, McBride OW, Gonzalez FJ (1987) Human P(3)450: cDNA and complete protein sequence, repetitive Alu sequences in the 3' nontranslated region, and localization of gene to chromosome 15. J Exp Pathol 3: 1-17.
  108. Crespi CL, Penman BW, Steimel DT, Gelboin HV, Gonzalez FJ (1991) The development of a human cell line stably expressing human CYP3A4: role in the metabolic activation of aflatoxin B1 and comparison to CYP1A2 and CYP2A3. Carcinogenesis 12: 355-359.
  109. Kirk GD, Lesi OA, Mendy M, Szymañska K, Whittle H, et al. (2005) 249(ser) TP53 mutation in plasma DNA, hepatitis B viral infection, and risk of hepatocellular carcinoma. Oncogene 24: 5858-5867.
  110. Eom SY, Yim DH, Lee CH, Choe KH, An JY, et al. (2015) Interactions between paraoxonase 1 genetic polymorphisms and smoking and their effects on oxidative stress and lung cancer risk in a Korean population. PLoS One 10: e0119100.
  111. Gertsch J (2008) Glutathione S-Transferase Pharm: The Comprehensive Pharmacology Reference, pp. 1-17.
  112. Ziglari T, Allameh A, Razzaghi-Abyaneh M, Khosravi AR, Yadegari MH (2008) Comparison of glutathione S-transferase activity and concentration in aflatoxin-producing and their non-toxigenic counterpart isolates. Mycopathologia 166: 219-226.
  113. Lumjuan N, Stevenson BJ, Prapanthadara LA, Somboon P, Brophy PM, et al. (2007) The Aedesaegypti glutathione transferase family. Insect Biochem Mol Biol 37: 1026-1035.
  114. Andersson C, Mosialou E, Weinander R, Morgenstern R (1994) Enzymology of microsomal glutathione S-transferase. Adv Pharmacol 27: 19-35.
  115. Warholm M, Guthenberg C, von Bahr C, Mannervik B (1985) Glutathione transferases from human liver. Methods Enzymol 113: 499-504.
  116. Mannervik B, Board PG, Hayes JD, Listowsky I, Pearson WR (2005) Nomenclature for mammalian soluble glutathione transferases. Methods Enzymol 401: 1-8.
  117. Pompella A, Visvikis A, Paolicchi A, De Tata V, Casini AF (2003) The changing faces of glutathione, a cellular protagonist. Biochem Pharmacol 66: 1499-1503.
  118. Oakley AJ, Lo Bello M, Nuccetelli M, Mazzetti AP, Parker MW (1999) The ligandin (non-substrate) binding site of human Pi class glutathione transferase is located in the electrophile binding site (H-site). J Mol Biol 291: 913-926.
  119. Kensler TW, Egner PA, Davidson NE, Roebuck BD, Pikul A, et al. (1986) Modulation of aflatoxin metabolism, aflatoxin-N7- guanine formation, and hepatic tumorogenesis in rats fed ethoxyquin: Role of induction of glutation S-transferases. Cancer Res 46: 3924-3931.
  120. Egner PA, Gange SJ, Dolan PM, Groopman JD, Muñoz A, et al. (1995) Levels of aflatoxin–albumin biomarkers in rat plasma are modulated by both long-term and transient interventions with oltipraz. Carcinogenesis 16: 1769-1773.
  121. Kimura M, Lehmann K, Gopalan-Kriczky P, Lotlikar PD (2004) Effect of diet on aflatoxin B1-DNA binding and aflatoxin B1-induced glutathione S-transferase placental form positive hepatic foci in the rat. Exp Mol Med 36: 351-357.
  122. Hofseth LJ, Hussain SP, Harris CC (2004) p53: 25 years after its discovery. Trends Pharmacol Sci 25: 177-181.
  123. Hsu IC, Metcalf RA, Sun T, Welsh JA, Wang NJ, et al. (1991) Mutational hotspot in the p53 gene in human hepatocellular carcinomas. Nature 350: 427-428.
  124. Smela ME, Currier SS, Bailey EA, Essigmann JM (2001) The chemistry and biology of aflatoxin B(1): from mutational spectrometry to carcinogenesis. Carcinogenesis 22: 535-545.
  125. Kirk G, Camus-Randon AM, Goedert J, Hainaut P, Montesano R. (1999) p53 mutation in sera of patients with hepatocellular carcinoma and cirrhosis in The Gambia (West Africa). [Abstract], AACR 90th Annual Meeting, 40: 41.
  126. Kirk GD, Camus-Randon AM, Mendy M, Goedert JJ, Merle P, et al. (2000) Ser-249 p53 mutations in plasma DNA of patients with hepatocellular carcinoma from The Gambia. J Natl Cancer Inst 92: 148-153.
  127. Kirk GD, Bah E, Montesano R (2006) Molecular epidemiology of human liver cancer: insights into etiology, pathogenesis and prevention from The Gambia, West Africa. Carcinogenesis 27: 2070-2082.
  128. Hulla JE, Chen ZY, Eaton DL (1993) Aflatoxin B1-induced rat hepatic hyperplastic nodules do not exhibit a site-specific mutation within the p53 gene. Cancer Res 53: 9-11.
  129. McMahon G, Davis EF, Huber LJ, Kim Y, Wogan GN (1990) Characterization of c-Ki-ras and N-ras oncogenes in aflatoxin B1-induced rat liver tumors. Proc Natl Acad Sci U S A 87: 1104-1108.
  130. Wogan GN, Hecht SS, Felton JS, Conney AH, Loeb LA (2004) Environmental and chemical carcinogenesis. Semin Cancer Biol 14: 473-486.
  131. Habib SL, Said B, Awad AT, Mostafa MH, Shank RC (2006) Novel adenine adducts, N7-guanine-AFB1 adducts, and p53 mutations in patients with schistosomiasis and aflatoxin exposure. Cancer Detect Prev 30: 491-498.
  132. Kamdem LK, Meineke I, Gödtel-Armbrust U, Brockmöller J, Wojnowski L (2006) Dominant contribution of P450 3A4 to the hepatic carcinogenic activation of aflatoxin B1. Chem Res Toxicol 19: 577-586.
  133. Hussain SP, Schwank J, Staib F, Wang XW, Harris CC (2007) TP53 mutations and hepatocellular carcinoma: insights into the etiology and pathogenesis of liver cancer. Oncogene 26: 2166-2176.
  134. Wang JS, Groopman JD (1999) DNA damage by mycotoxins. Mutat Res 424: 167-181.
  135. Domínguez-Malagón H, Gaytan-Graham S (2001) Hepatocellular carcinoma: an update. Ultrastruct Pathol 25: 497-516.
  136. Tashiro F, Morimura S, Hayashi K, Makino R, Kawamura H, et al. (1986) Expression of the c-Ha-ras and c-myc genes in aflatoxin B1-induced hepatocellular carcinomas. Biochem Biophys Res Commun 138: 858-864.
  137. McMahon G, Hanson L, Lee JJ, Wogan GN (1986) Identification of an activated c-Ki-ras oncogene in rat liver tumors induced by aflatoxin B1. Proc Natl Acad Sci U S A 83: 9418-9422.
  138. Sinha S, Webber C, Marshall CJ, Knowles MA, Proctor A, et al. (1988) Activation of ras oncogene in aflatoxin-induced rat liver carcinogenesis. Proc Natl Acad Sci U S A 85: 3673-3677.
  139. Wild CP, Hall AJ (2000) Primary prevention of hepatocellular carcinoma in developing countries. Mutat Res 462: 381-393.
  140. Hussain SP, Harris CC (1998) Molecular epidemiology of human cancer. Recent Results Cancer Res 154: 22-36.
  141. Soini Y, Chia SC, Bennett WP, Groopman JD, Wang JS, et al. (1996) An aflatoxin-associated mutational hotspot at codon 249 in the p53 tumor suppressor gene occurs in hepatocellular carcinomas from Mexico. Carcinogenesis 17: 1007-1012.
  142. Coursaget P, Depril N, Chabaud M, Nandi R, Mayelo V, et al. (1993) High prevalence of mutations at codon 249 of the p53 gene in hepatocellular carcinomas from Senegal. Br J Cancer 67: 1395-1397.
  143. Laurent-Puig P, Legoix P, Bluteau O, Belghiti J, Franco D, et al. (2001) Genetic alterations associated with hepatocellular carcinomas define distinct pathway of hepatocarcinogenesis. Gastroenterology 120: 1763-1773.
  144. Logan CY, Nusse R (2004) The Wnt signaling pathway in development and disease. Annu Rev Cell Dev Biol 20: 781-810.
  145. Komiya Y, Habas R (2008) Wnt signal transduction pathways. Organogenesis 4: 68-75.
  146. Wong CM, Fan ST, Ng IO (2001) beta-Catenin mutation and overexpression in hepatocellular carcinoma: clinicopathologic and prognostic significance. Cancer 92: 136-145.
  147. Nhieu JT, Renard CA, Wei Y, Cherqui D, Zafrani ES, et al. (1999) Nuclear accumulation of mutated beta-catenin in hepatocellular carcinoma is associated with increased cell proliferation. Am J Pathol 155: 703-710.
  148. Fang Y, Feng Y, Wu T, Srinivas S, Yang W, et al. (2013) Aflatoxin B1 negatively regulates Wnt/β-catenin signaling pathway through activating miR-33a. PLoS One 8: e73004.
  149. Jacobsen JS, Refolo LM, Conley MP, Sambamurti K, Humayun MZ (1987) DNA replication-blocking properties of adducts formed by aflatoxin B1-2,3-dichloride and aflatoxin B1-2,3-oxide. Mutat Res 179: 89-101.
  150. Campbell TC, Caedo JP Jr, Bulatao-Jayme J, Salamat L, Engel RW (1970) Aflatoxin M1 in human urine. Nature 227: 403-404.
  151. IARC, International Agency for the Research on Cancer (1982) IARC/IPCS Working Group. Development and possible use of immunological techniques to detect individual exposure to carcinogenesis. IARC Intern Tech Rep No 82/001, 25. Lyon, France.
  152. Wild CP, Garner RC, Montesano R, Tursi F (1986) Aflatoxin B1 binding to plasma albumin and liver DNA upon chronic administration to rats. Carcinogenesis 7: 853-858.
  153. Groopman JD, Donahue PR, Zhu JQ, Chen JS, Wogan GN (1985) Aflatoxin metabolism in humans: detection of metabolites and nucleic acid adducts in urine by affinity chromatography. Proc Natl Acad Sci U S A 82: 6492-6496.
  154. Zhu JQ, Zhang LS, Hu X, Xiao Y, Chen JS, et al. (1987) Correlation of dietary aflatoxin B1 levels with excretion of aflatoxin M1 in human urine. Cancer Res 47: 1848-1852.
  155. Croy RG, Essigmann JM, Reinhold VN, Wogan GN (1978) Identification of the principal aflatoxin B1-DNA adduct formed in vivo in rat liver. Proc Natl Acad Sci U S A 75: 1745-1749.
  156. Essigmann JM, Croy RG, Nadzan AM, Busby WF Jr, Reinhold VN, et al. (1977) Structural identification of the major DNA adduct formed by aflatoxin B1 in vitro. Proc Natl Acad Sci U S A 74: 1870-1874.
  157. Hertzog PJ, Smith JR, Garner RC (1982) Characterisation of the imidazole ring-opened forms of trans-8,9-dihydro-8,9-dihydro-8-(7-guanyl)9-hydroxy aflatoxin B1. Carcinogenesis 3: 723-725.
  158. Sotomayor RE, Washington M, Nguyen L, Nyang'anyi R, Hinton DM, et al. (2003) Effects of intermittent exposure to aflatoxin B1 on DNA and RNA adduct formation in rat liver: dose-response and temporal patterns. Toxicol Sci 73: 329-338.
  159. Jennings GS, Oesch F, Steinberg P (1992) In vivo formation of aflatoxin B1-DNA adducts in parenchymal and non-parenchymal cells of rat liver. Carcinogenesis 13: 831-835.
  160. Riley J, Mandel HG, Sinha S, Judah DJ, Neal GE (1997) In vitro activation of the human Harvey-ras proto-oncogene by aflatoxin B1. Carcinogenesis 18: 905-910.
  161. USAID (2004) Famine Early Warning Systems Network (Kenya), World Food Program, Kenya Ministry of Agriculture. Kenya food security report.
  162. African Agricultural Technology Foundation (AATF) (2007) Accessed on Sept 6, 2015.
  163. Lee HS, Sarosi I, Vyas GN (1989) Aflatoxin B1 formamidopyrimidine adducts in human hepatocarcinogenesis: a preliminary report. Gastroenterology 97: 1281-1287.
  164. Loury DN, Hsieh DP (1984) Effects of chronic exposure to aflatoxin B1 and aflatoxin M1 on the in vivo covalent binding of aflatoxin B1 to hepatic macromolecules. J Toxicol Environ Health 13: 575-587.
  165. Ross MK, Said B, Shank RC (2000) DNA-damaging effects of genotoxins in mixture: modulation of covalent binding to DNA. Toxicol Sci 53: 224-236.
  166. Chlouchi A, Girard C, Bonet A, Viollon-Abadie C, Heyd B, et al. (2007) Effect of chrysin and natural coumarins on UGT1A1 and 1A6 activities in rat and human hepatocytes in primary culture. Planta Med 73: 742-747.
  167. Izzotti A, Bagnasco M, Cartiglia C, Longobardi M, Camoirano A, et al. (2005) Modulation of multigene expression and proteome profiles by chemopreventive agents. Mutat Res 591: 212-223.
  168. Min Jung K, Dong-Hyun K. (2007) Disposition and metabolism of dietary flavonoids. Chapter 28. In: Losso JN, Shahidi F, Bagchi D (eds). Medicinal Foods Nutraceutical Science and Technology. Series 6. Edit Shahidi F. CRC Press Taylor and Francis Group. Boca Raton FL, USA.
  169. Urban JD, Clarke WP, von Zastrow M, Nichols DE, Kobilka B, et al. (2007) Functional selectivity and classical concepts of quantitative pharmacology. J Pharmacol Exp Ther 320: 1-13.
  170. Stresser DM, Williams DE, McLellan LI, Harris TM, Bailey GS. (1994) Indole-3-carbinol induces a rat liver glutathione transferase subunit (Yc2) with high activity toward AFB1 exo-epoxide. Association with reduced levels of hepatic AF-DNA adducts in vivo. Drug Metab Dispos 22: 392-399.
  171. Takahashi N, Harttig U, Williams DE, Bailey GS (1996) The model Ah-receptor agonist beta-naphthoflavone inhibits aflatoxin B1-DNA binding in vivo in rainbow trout at dietary levels that do not induce CYP1A enzymes. Carcinogenesis 17: 79-87.
  172. Casper RF, Quesne M, Rogers IM, Shirota T, Jolivet A, et al. (1999) Resveratrol has antagonist activity on the aryl hydrocarbon receptor: implications for prevention of dioxin toxicity. Mol Pharmacol 56: 784-790.
  173. Henry EC, Kende AS, Rucci G, Totleben MJ, Willey JJ, et al. (1999) Flavone antagonists bind competitively with 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) to the aryl hydrocarbon receptor but inhibit nuclear uptake and transformation. Mol Pharmacol 55: 716-725.
  174. Im SH, Bolt MW, Stewart RK, Massey TE (1996) Modulation of aflatoxin B1 biotransformation by beta-naphthoflavone in isolated rabbit lung cells. Arch Toxicol 71: 72-79.
  175. Pelkonen P, Lang M, Wild CP, Negishi M, Juvonen RO. (1994) Activation of aflatoxin B1 by mouse CYP2A enzymes and cytotoxicity in recombinant yeast cells. Eur J Pharmacol 292: 67-73.
  176. Knight LP, Primiano T, Groopman JD, Kensler TW, Sutter TR (1999) cDNA cloning, expression and activity of a second human aflatoxin B1-metabolizing member of the aldo-keto reductase superfamily, AKR7A3. Carcinogenesis 20: 1215-1223.
  177. Hayes JD, Judah DJ, Neal GE (1993) Resistance to AFB1 is associated with the expression of a novel aldo-keto reductase which has catalytic activity towards a cytotoxic aldehyde-containing metabolite of the toxin. Cancer Res 53: 3887-3894.
  178. Tamimi RM, Lagiou P, Adami HO, Trichopoulos D (2002) Prospects for chemoprevention of cancer. J Intern Med 251: 286-300.
  179. Egner PA, De Matos P, Groopman JD, Kensler TW (1990) Effect of 1,2-dithiole-3-thione, a monofunctional enzyme inducer, on Aflatoxin -DNA adduct formation in rat liver. Proc - Annual Meet Amer Assoc Cancer Res, USA. 31: 119.
  180. Benson AB 3rd (1993) Oltipraz: a laboratory and clinical review. J Cell Biochem Suppl 17F: 278-291.
  181. Salbe AD, Bjeldanes LF (1989) Effect of diet and route of administration on the DNA binding of aflatoxin B1 in the rat. Carcinogenesis 10: 629-634.
  182. Kensler TW (1997) Chemoprevention by inducers of carcinogen detoxication enzymes. Environ Health Perspect 105 Suppl 4: 965-970.
  183. Kensler TW, Chen JG, Egner PA, Fahey JW, Jacobson LP, et al. (2005) Effects of glucosinolate-rich broccoli sprouts on urinary levels of Aflatoxin-DNA adducts and phenanthrenetetraols in a randomized clinical trial in HeZuo Township, Qidong, People's Republic of China. Cancer Epidemiol Biomarkers Prev 14: 2605-2613.
  184. Bolton MG, Muñoz A, Jacobson LP, Groopman JD, Maxuitenko YY, et al. (1993) Transient intervention with oltipraz protects against aflatoxin-induced hepatic tumorigenesis. Cancer Res 53: 3499-3504.
  185. O'Dwyer PJ, Szarka CE, Yao KS, Halbherr TC, Pfeiffer GR, et al. (1996) Modulation of gene expression in subjects at risk for colorectal cancer by the chemopreventive dithiolethione oltipraz. J Clin Invest 98: 1210-1217.
  186. Allameh A (1997) Comparison of the effect of low- and high-dose dietary butylated hydroxytoluene on microsome-mediated aflatoxin B1-DNA binding. Cancer Lett 114: 217-220.
  187. Salocks CB, Hsieh DP, Byard JL (1984) Effects of butylated hydroxytoluene pretreatment on the metabolism and genotoxicity of AFB1 in primary cultures of adult rat hepatocytes: selective reduction of nucleic acid binding. Toxicol Appl Pharmacol 76: 498-509.
  188. Mandal S, Ahuja A, Shivapurkar NM, Cheng SJ, Groopman JD, et al. (1987) Inhibition of aflatoxin B1 mutagenesis in Salmonella typhimurium and DNA damage in cultured rat and human tracheobronchial tissues by ellagic acid. Carcinogenesis 8: 1651-1656.
  189. Donnelly PJ, Stewart RK, Ali SL, Conlan AA, Reid KR, et al. (1996) Biotransformation of aflatoxin B1 in human lung. Carcinogenesis 17: 2487-2494.
  190. Shi CY, Chua SC, Lee HP, Ong CN (1994) Inhibition of aflatoxin B1-DNA binding and adduct formation by selenium in rats. Cancer Lett 82: 203-208.
  191. Gyamfi MA, Aniya Y (1998) Medicinal herb, Thonningiasanguinea protects against aflatoxin B1 acute hepatotoxicity in Fischer 344 rats. Hum Exp Toxicol 17: 418-423.
  192. Kelly VP, Ellis EM, Manson MM, Chanas SA, Moffat GJ, et al. (2000) Chemoprevention of Aflatoxin B1 hepatocarcinogenesis by coumarin, a natural benzopyrone that is a potent inducer of Aflatoxin B1-aldehyde reductase, the glutathione S-transferase A5 and P1 subunits, and NAD(P)H: Quinone oxidoreductase in Rat Liver. Cancer Res 60: 957-969.
  193. Cavin C, Holzhauser D, Constable A, Huggett AC, Schilter B (1998) The coffee-specific diterpenes cafestol and kahweol protect against AFB1-induced genotoxicity through a dual mechanism. Carcinogenesis 19: 1369-1375.
  194. Yates MS, Kwak MK, Egner PA, Groopman JD, Bodreddigari S, et al. (2006) Potent protection against aflatoxin-Induced tumorigenesis through Induction of Nrf2-regulated pathways by the triterpenoid-[2-cyano-3-,12-dioxooleana-1,9(11)-dien-28-oyl] imidazole. Cancer Res 66: 2488-2494.
  195. Elegbede JA, Gould MN. (2002) Monoterpenes reduced adducts formation in rats exposed to aflatoxin B1. African J Biotech 1: 46-49.
  196. Miyata M, Takano H, Guo LQ, Nagata K, Yamazoe Y (2004) Grapefruit juice intake does not enhance but rather protects against AFB1-induced liver DNA damage through a reduction in hepatic CYP3A activity. Carcinogenesis 25: 203-209.
  197. Gradelet S, Le Bon AM, Bergès R, Suschetet M, Astorg P (1998) Dietary carotenoids inhibit aflatoxin B1-induced liver preneoplastic foci and DNA damage in the rat: role of the modulation of aflatoxin B1 metabolism. Carcinogenesis 19: 403-411.
  198. Netke SP, Roomi MW, Tsao C, Niedzwiecki A (1997) Ascorbic acid protects guinea pigs from acute aflatoxin toxicity. Toxicol Appl Pharmacol 143: 429-435.
  199. Reddy L, Odhav B, Bhoola K (2006) Aflatoxin B1-induced toxicity in HepG2 cells inhibited by carotenoids: morphology, apoptosis and DNA damage. Biol Chem 387: 87-93.
  200. Wong BY, Lau BH, Yamasaki T, Teel RW (1993) Inhibition of dexamethasone-induced cytochrome P450-mediated mutagenicity and metabolism of aflatoxin B1 by Chinese medicinal herbs. Eur J Cancer Prev 2: 351-356.
  201. Chang HM and But PPH (eds) (1986) Pharmacology and Applications of Chinese Materia Medica. World Scientific, Singapore.
  202. Bensky D, Gamble A (1993) Chinese Herbal Medicine: Materia Medica, Eastland Press, Seattle, WA.
  203. Minyi C (1992) Anticancer Medicinal Herbs. Hunan Science and Technology Publishing House, Changsha.
  204. Ou M, Xu H, Li Y (1990) An Illustrated Guide to Antineoplastic Chinese Herbal Medicine. The Commercial Press, Hong Kong.
  205. Mitchell C (translators) (2003) Ten Lectures on the Use of Medicinals from the Personal Experience of Jiao Shude, 2003 Paradigm Publications, Brookline, MA.
  206. Gupta S, Zhang D, Yi J, Shao J (2004) Anticancer activities of Oldenlandia diffusa. J Herb Pharmacother 4: 21-33.
  207. Shan BE, Zhang JY, Du XN (2001) [Immunomodulatory activity and anti-tumor activity of Oldenlandia diffusa in vitro]. Zhongguo Zhong Xi Yi Jie He ZaZhi 21: 370-374.
  208. Yoshida Y, Wang MQ, Liu JN, Shan BE, Yamashita U (1997) Immunomodulating activity of Chinese medicinal herbs and Oldenlandia diffusa in particular. Int J Immunopharmacol 19: 359-370.
  209. Wong BY, Lau BH, Jia TY, Wan CP (1996) Oldenlandia diffusa and Scutellaria barbata augment macrophage oxidative burst and inhibit tumor growth. Cancer BiotherRadiopharm 11: 51-56.
  210. Cha YY, Lee EO, Lee HJ, Park YD, KO SG, et al. (2004) Methylene chloride fraction of Scutellaria barbatainduces apoptosis in human U937 leukemia cells via the mitochondrial signaling pathway. Clinica Chimica Acta 348: 41-48.
  211. Yin X, Zhou J, Jie C, Xing D, Zhang Y (2004) Anticancer activity and mechanism of Scutellaria barbata extract on human lung cancer cell line A549. Life Sci 75: 2233-2244.
  212. Guangcheng X, Dehua L (Eds) (2000) Color Atlas of Anticancer Animal, Plant, and Mineral Preparations and their Applications, Tianjin Science & Technology Translation Press, Tianjin
  213. Dharmananda S (2004) A Bag of Pearls, Institute for Traditional Medicine, Portland, OR.
  214. Egner PA, Wang JB, Zhu YR, Zhang BC, Wu Y, et al. (2001) Chlorophyllin intervention reduces aflatoxin-DNA adducts in individuals at high risk for liver cancer. Proc Natl Acad Sci U S A 98: 14601-14606.
  215. El-Nezami HS, Polychronaki NN, Ma J, Zhu H, Ling W, et al. (2006) Probiotic supplementation reduces a biomarker for increased risk of liver cancer in young men from Southern China. Am J Clin Nutr 83: 1199-1203.
  216. Unión Ganadera Regional de Jalisco (2015) Regional livestock Union of Jalisco.
  217. Elbein AD (1969) Biosynthesis of a cell wall glucomannan in mung bean seedlings. J Biol Chem 244: 1608-1616.
  218. Tokoh C, Takabe K, Sugiyama J, Fujita M (2002) CP/MAS 13C NMR and electron diffraction study of bacterial cellulose structure affected by cell wall polysaccharides. Cellulose 9: 351-360.
  219. Chorvatovicová D, Machová E, Šandula J, Kogan G (1999) Protective effect of the yeast glucomannan against cyclophosphamide-induced mutagenicity. Mutat Res 444: 117-122.
  220. Van Egmond HP, Jonker MA (2005) Worldwide regulations on aflatoxins- The Situation in 2002. In: Abbas HK (ed). Aflatoxin and food safety. Taylor & Francis, Boca Raton, Florida, USA pp. 77-93.
Citation: Carvajal-Moreno M (2015) Metabolic Changes of Aflatoxin B1 to become an Active Carcinogen and the Control of this Toxin. Immunome Res 11:104.

Copyright: © Carvajal-Moreno M. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.